1. Field of the Invention
The present invention relates to optical fibers and more particularly to the attachment of optical fibers to Opto-Electronic Integrated Circuits on silicon substrates.
2. Description of the Prior Art
Optical fibers provide useful transmission of optical power from one location to another; at each end of the fiber, an attachment must be made to some other device, or to another fiber. Frequently, the attachment of the fiber to a terminal device, (either a source or a receiver of the optical power), is more likely to present a problem of cost or reliability than either the fiber or the terminal device per se. This is particularly true of the attachment of fibers to Opto-Electronic Integrated Circuits (OEICs) which are becoming the preferred receiving devices. Current methods of attaching fibers to such devices require expensive, very precise and time-consuming mechanisms to align the fiber to the optical waveguides of the OEIC within tolerances of a micron or less, which alignment must be maintained over the lifetime of the device, possibly for decades. Opto-Electronic Integrated Circuits on silicon substrates promise to become widely used because of the extensive technical and industrial base of electronic circuitry on silicon substrates.
A method which permits the attachment of optical fiber to be made to such OEICs quickly and simply with a minimum of equipment and operator skill would greatly expand the usefulness of this technology to new applications and markets.
Techniques for automatic ("Blind") alignment of single-mode fibers to integrated opto-electronic circuits using fiber grooves in silicon have been demonstrated in C. A. Armiento et al, "Passive Coupling of InGaAsP/InP Laser Array and Single-Mode Fibers Using Silicon Waferboard", Elect. Lett. 27, p. 1109-1110, 1991 and M. S. Cohen et al, "Passive Laser-Fiber Alignment By Index Method", Photonics Technology Letters, v.3 p. 985-987, 1991. These techniques generally have used two separate pieces: one with the grooves and a vertical cleaved or polished face perpendicular to the grooves and the surface, and the other with the waveguides on the surface and a perpendicular vertical surface on which the ends of the waveguides are accessible. These techniques are illustrated in FIGS. 1-3.